High impulse propellants



3,618,202 Patented Jan. 23, 1962 3,018,202 HEGH lit {PULSE PRUPELLANTS Winston E. Brown, Lake Jackson, and Marshall W.

Mabry, McGregor, Tex, assignors to Phillips Petroleum Company, a corporation of Delaware No Drawing. Filed Aug. 9, 1957, Ser. No. 677,408 15 Claims. (Cl. 149-119) This invention relates to high impulse propellants. In one aspect this invention relates to high impulse propellant compositions. In another aspect this invention relates to amethod of preparing high impulse propellants. In still anoii, er aspect this invention relates to a method of preparing fill-rd rubber compositions.

In recent year... considerable work has been directed toward the development of solid propellants suitable for use in rocket motor... Rockets employing solid propellant fuels are extensively used by the military and have also achieved considerable importance in commercial operations. For example, solid rocket propellants are utilized in missiles, projectiles, and rockets to assist planes in take-01f or to furnish an extra surge of power in flight. A sol-id propellant to be satisfactory for its intended use should possess certain desirable physical characteristics, for example, the propellant should have a high tensile strength and a high modulus of elasticity.

Recently, superior solid propellant materials have been discovered which comprise a solid oxidant, such as ammonium nitrate or ammonium perchlorate, and a rubbery material, such as a copolymer of butadiene and a vinylpyridine or other substituted heterocyclic nitrogen base compound, which after incorporation is cured by a quaternization reaction or a vulcanization reaction. Solid propellant mixtures of this nature and a process for their production are disclosed and claimed in copending application, Serial No. 284,447, filed April 25, 1952, by W. B. Reynolds and I. E. Pritchard.

In the production of solid propellants it is ordinarily desirable that said propellants have excellent mechanical properties such as high elongation and high tensile strength. However, for some special purpose propellants the mechanical properties are of secondary importance. This is frequently the situation where a high impulse propellant is desired for certain specific uses. A high impulse propellant can be defined as one having a high burning rate and which thus produces large volumes of gas in relatively short periods of time. Such high impulse propellants are frequently desired for use in relatively small missiles such as air-to-air missiles, groundto-air missiles and stationary gas generators and where the physical properties of the propellant itself are of secondary importance.

High impulse propellants require high oxidizer loadings. It has recently been discovered that liquid diene polymers, such as liquid polybutadiene, are excellent plasticizers for the rubbery copolymers which are frequently employed as the binder component in solid propellants. We have discovered a method for formulating high impulse propellants using liquid diene polymers as a plasticizer whereby it is possible to obtain especially high oxidizer loadings. We have also discovered that by using activated charcoal in the propellant formulation that we can provide high impulse propellants having burning rates from two to three times the burning rate of similar prior art propellants. Said activated charcoal can, if desired, function as the sole curing agent and the sole burning rate catalyst in the propellant formulation.

Thus, broadly speaking, the propellant compositions of the invention comprises a binder component, an oxidizer component and activated charcoal.

An object of this invention is to provide a high impulse propellant. Another object of this invention is to provide a method of formulating a high impulse propellant having a high oxidizer loading. Another object of this invention is to provide a high impulse propellant wherein activated charcoal is the sole curing agent and the sole burning rate catalyst. Still another object of this invention is to provide a method of preparing filled rubber compositions. Other aspects, objects, and advantages of the invention will be apparent to those skilled in the art in view of this disclosure.

Thus, according to the invention there is provided a propellant composition comprising: from 4 to 16 parts by weight of a binder component; from 88 to 94 parts by weight of ammonium nitrate; and from 4 to 12 parts by weight of activated charcoal.

Further according to the invention, there is provided a method of preparing a filled rubber composition wherein said rubber, together with a plasticizer therefor, forms a binder for a finely divided solid filler material, which method comprises: intimately blending said plasticizer with said rubber to form said binder; incorporating from 7 to 12 weight percent of the total filler material into said binder to form a filled rubber masterbatch; dividing the remainder of said filler material into a plurality of portions or increments; and successively incorporating said increments into said masterbatch.

In the propellants of this invention, the binder component comprises a rubbery copolymer together with a plasticizer therefor. Said copolymer can be employed in amounts of from 2 to 10 parts by weight, preferably from 2 to 4 parts by weight, based on the total propellant composition. Said plasticizer can be employed in amounts from 2 to 6 parts by weight, preferably 2 parts by weigh-t, based on the tot-al'propellant composition.

The rubbery polymers employed as binders in the solid propellant compositions of this invention .are copoly: mers of conjugated dienes with polymerizable heterocyclic nitrogen bases of the pyridine series. These copolymers can vary in consistency from very soft rubbers, i.e., materials which are soft at room temperature but will show retraction when relaxed, to those having a Mooney value (ML-4) up to 100. The rubber copolymers most frequently preferred have Mooney values in the range between 10 and 40. They may be prepared by any polymerization methods known to the art, e.g., mass or emulsion polymerization. One convenient method for'preparing these copolymers is by emulsion polymerization at temperatures in the range between 0 and 140 F. Recipes such as the iron pyrophosphate-hydroperoxide, either sugar-free or containing sugar, the sulfoxylate, and the persulfate recipes are among those which are applicable. It is advantageous to polymerize to high conversion as the unreacted vinylpyridine monomer is difiicult to remove by stripping. Said copolymers can have carbon black incorporated therein in an amount within the range of 0 to 30 parts of carbon black per parts of copolymer.

The conjugated dienes employed are those containing from 4 to 8 carbon atoms per molecule and include 1,3-butadiene, i-soprene, Z-methyI-IJ-butadiene, 2,3-dimethyl-l,3-butadiene, Z-methoxybutadiene, Z-phenylbutadiene, and the like. Various alkoxy, such as methoxy and ethoxy and cyano derivatives of these conjugated dienes, are also applicable. Thus, other dienes, such as phenylbutadiene, 2,3-dimethyl-1,3-hexadiene, 2-methoxy- 3-ethylbutadiene, 2-ethoxy-3-ethyl-l,3-hexadiene, 2-cyano-1,3-butadiene, are also applicable in the preparation of the polymeric binders of this invention. Furthermore, instead of using a single conjugated diene, a mixture of conjugated dienes can be employed. Thus, a mixture of 1,3-butadiene and isopre-ne can be employed as the conjugated diene portion of the system.

The polymerizable heterocyclic nitrogen bases which are applicable for the production of the polymeric materials are those of the pyridine, quinoline, and isoquinoline series which are copolymerizable with a conjugated diene and contain one, and only one,

B! CH2 (3 substituent wherein R is either hydrogen or a methyl group. That is, the substituent is either a vinyl or an alpha-methylvinyl (isopropenyl) group. Of these, the compounds of the pyridine series are at present of the greatest interest commercially. Various substituted derivatives are also applicable but the total number of carbon atoms in the groups attached to the carbon atoms of the heterocyclic nucleus should not be greater than 15 because the polymerization rate decreases somewhat with increasing size of the alkyl group. Compounds where the alkyl substituents are methyl and/ or ethyl are available commercially.

These heterocyclic nitrogen bases have the formula where R is. selected from the group consisting of hydrogen, alkyl, vinyl, alpha-methylvinyl, alkoxy, halo, hydroxy, cyano, aryloxy, aryl, and combinations of these groups such as haloalkyl, alkylaryl, hydroxyaryl, and the like; one and only one of said groups being selected from the group consisting of vinyl and alpha-methylvinyl; and the total number of carbon atoms in the nuclear substituted groups being not greater than 15. Examples of such compounds are 2-vinylpyridine; 2-vinyl-5-ethylpyridine; 2-methyl-5-vinylpyridine; 4-vinylpyridine; 2,3,4-trimethyl-S-vinylpyridine; 3,4,5,6 tetramethyl-2-vinylpyridine; 3-ethyl-5-vinylpyridine; 2,6-diethyl-4-vinylpyridine; 2-isopropyl-4-nonyl-5-vinylpyridine; Z-methyI-S-undecyl- 3-vinylpyridine; 2,4-dimethyl-5,6-dipentyl-3-vinylpyridine; 2-decyl-5-(alpha-methylvinyl)pyridine; 2-vinyl-3-methyl- 5 -ethylpyridine; 2-metl1oxy-4-chloro-6-vinylpyridine; 3- vinyl-S-ethoxypyridine; 2 -vinyl-5,5-dichloropyridine; 2- (alpha-methylvinyl)-4-hydroxy-6-cyanopyridine; 2-vinyl- 4 phenoxy-S-methylpyridine; 2-cyano-5-(alpha-methylvinyl)pyridine; 3-vinyl-5-phenylpyridine; 2-(para-methylphenyl)-3-vinyl-4-methylpyridine; 3 vinyl-S-(hydroxyphenyl)-pyridine; 2-vinylquinoline; 2-vinyl-4-ethylquinoline; 3-vinyl-6,7-di-n-propylquinoline; 2-methyl-5-nonyl-6- vinylquinoline; 4-(alpha-methylvinyl) 8 dodecylquinoline; 3-vinylisoquinoline; l,G-dimethyl-3-vinyl-isoquinoline; 2-vinyl-4-benzylquinoline; 3-vinyl-S-chloroethylquinoline; 3-vinyl-5,6-dichloroisoquinoline; 2-vinyl-6-ethoxy- 7 -methylquinoline; 3 vinyl-fi-hydroxymethylquinoline; and the like.

The presently preferred plasticizer is a liquid polybutadiene prepared by mass polymerization in the presence of finely divided sodium as the catalyst according to the method of Crouch, 2,631,175. Broadly, the plasticizers which can be used in accordance with this invention comprise liquid polymers prepared from conjugated diolefin hydrocarbons such as 1,3-butadiene and isoprene, the

liquid polymers having a viscosity of to 5000 Saybolt Furol seconds at 100 F. Polymers having a viscosity from about 1000 to about 2500 Saybolt Furol seconds are presently preferred. These liquid polymers can be prepared by emulsion polymerization using large amounts of modifiers in accordance with the teaching of Frolich et al., 2,500,983, although, they are preferably prepared by the method set forth in Crouch, 2,631,175. The latter method comprises mass polymerization in the presence of finely divided alkali metal and/or alkali metal hydride such as sodium, potassium lithium, sodium hydride, potassium hydride and lithium hydride.

Polymers thus prepared contain no modifiers or viscositycontrolling agent and they are also free of materials which would act as inhibitors such as antioxidants and shortstops. Finely divided catalyst is used, .p referably having a particle size below 200 microns rfiid generally below 100 microns in the range of 40 toB- J microns. The amount of catalyst employed usually "oes not exceed 2 parts by weight of the total monong. charged, preferably in the range of 0.5 to 1.5 a is by weight per 100 parts monomer. A more complete description of the process is set forth in the Crouch patent identified above.

While liquid diene polymers are the presently preferred plasticizers, it is within the scope of the invention to employ other plasticizers. Materials such as Pentaryl A (amylbiphenyl), Para-Flux (saturated polymerized hydrocarbon), Circosol-ZXH (petroleum hydrocarbon softener having a specific gravity of 0.940 and a Saybolt Universal viscosity at 100 F. of about 2000 seconds), di-butoxyethoxyethyl formal, and dioctyl phthalate are suitable plasticizers. Materials which provide rubber having good low temperature properties are preferred. It is also frequently preferred that the plasticizers be oxygen-containing materials.

Oxidants which are applicable in the solid propellant compositions of this invention include ammonium, alkali metal, and alkaline earth metal salts of nitric and perchloric acid. Ammonium nitrate is the presently preferred oxidant for use in the solid rocket fuels of this invention. Specific oxidants include ammonium perchlo' rate, sodium nitrate, potassium perchlorate, potassium nitrate, calcium nitrate, and barium perchlorate. Mixtures of oxidants are also applicable. In the preparation of the solid rocket propellant compositions, the oxidants are powdered to sizes preferably finer than 200 mesh. The amount of solid oxidant employed is within the range of 88 to 94 parts by weight, preferably 92 to 94 parts by weight, based on the total weight of the propellant.

Wetting agents aid in defiocculating or dispersing the oxidizer. Aerosol OT (dioctyl ester of sodium sulfosuccinic acid), lecithin, and Duomeen C diacetate (reaction product of acetic acid with the mono-salt formed from trimethylene diamine and coconut oil acid) are among the materials which can be employed.

Antioxidants include Flexamine (physical mixture containing 65 percent of a complex diarylamine-ketone reaction product and 35 percent of N,N-diphenyl-p-phenylenediamine), phenyl-beta-naphthylamine, 2,2-methylenebis(4-methyl-6-tert-butylphenol), and the like. Rubber antioxidants, in general, may be employed, or if desired, they may be omitted.

In a presently preferred embodiment of the invention the activated charcoal forms the sole burning rate catalyst for the oxidant. However, other burning rate catalyst can be employed in conjunction with said activated charcoal if desired. One such other presently preferred catalyst is ammonium dichromate. Said ammonium dichromate is powdered to sizes less than 44 microns, more preferably within the range of 3 to 12 microns. Other burning rate catalysts such as metal ferrocyanides and ferricyanides can also be used. Ferric ferrocyanides, such as Prussian, Berlin, Hamburg, Chinese, Paris, and milori blue, soluble ferric ferrocyanide, such as soluble Berlin or Prussian blue which contains potassium ferric ferrocyanide, and ferric ferrocyanide which has been treated with ammonia, are among the materials which can be used. Ferrous ferricyanide, Turnbulls blue, is also applicable. A particularly effective burning rate catalyst is milori blue which is a pigment similar to Prussian blue but having a red tint and is prepared by the oxidation of a paste of potassium ferrocyanide and ferrous sulfate. Other metal compounds such as nickel and copper ferrocyanides can also be employed. The amount of burning rate catalyst, other than activated charcoal, used in the propellant compositions of this invention is usually in the range of 0 to 4 parts by weight based on the total weight of the propellant.

Presently preferred activated charcoals for use in the practice of the invention are those made by carbonizing lignite,waste wood pulp, liquors, black ash residues, saw dust, woods, and similar materials in carbonizing retorts under controlled conditions of temperature and atmosphere. After carbonization the charcoal is gas activated, usually by air or mixtures of steam. and air. Activated charcoals having the following characteristics form a presently preferred class of charcoals for use according to the invention; percent carbon 97 to 98; percent ash 2 to 8; percent soluble in HCl 0.5 to 4; and water extract pH 4 to 8.5. A presently preferred activated charcoal is Norit A, a commercially available product.

In the production of solid propellant mixtures of the invention, the ratio of oxidant to binder is very high. It is necessary that the rubber binder of such propellant mixtures be the continuous phase in which the oxidant is dispersed in order to obtain satisfactory consolidation so that upon curing a solid material of sufficient structural strength will be obtained. Heretofore, one of the difficulties encountered in the manufacture of propellants of this type has been that of loss of a continuous phase whereby the binder forms a discontinuous phase in the oxidizer. When the continuous phase is lost in this manner, the batch cannot be used to prepare a propellant charge and must be discarded or reprocessed in some manner. An additional difficulty attendant with a mixture having a tendency toward loss of continuous phase is that the mixing time required to obtain a satisfactory product is greatly extended. In order to properly and quickly prepare the propellants of the invention, we have developed the novel mixing procedure of the invention. In the practice of the invention the mixing can be accomplished in mixers of the kneader type such as those with vertically or horizontally mounted blades or Banbury type mixers. It is desirable that said mixers be fitted with interchangeable attachments such as compression rams, vacuum heads, etc. A compression ram exerting considerable force on the ingredients can be advantageously applied during the mixing stages, particularly during the final mixing stage. Vacuum can be applied to remove entrained air and/or moisture.

In the practice of the invention our mixing procedure, in general, comprises first preparing a propellant masterbatch of the binder together with a portion of the oxidant. Said masterbatch is prepared by first kneading the copolymer for a short period of time in a suitable mixer such as a Baker-Perkins mixer. If desired, this kneading can be carried out under a partial vacuum up to 26-29 inches of mercury so as to remove any moisture which may be present in the copolymer. The plasticizer and from about 7 to about 12 percent of the total solids to be added to the binder are then introduced and said solids are incorporated into the binder by mixing for a sufiicient length of time. If desired, the compression ram on the mixer can be lowered during this mixing step. Also if desired, a partial vacuum can be employed during the latter portion of this mixing step so as to remove air which may have been incorporated into the binder.

The thus prepared masterbatch can then be removed from the mixer and stored for use as desired or the formulation of the finished propellant can continue as follows. If the propellant masterbatch has been stored the desired quantity thereof is added to the mixer and kneaded for a short period of time, usually about two minutes. The remainder of the oxidant component is then divided into a plurality of portions or increments; preferably equal. The number of increments is dependent upon the amount of oxidant to be incorporated into the binder and will usually range from 3 to 6. Each increment is added to the mixture in the mixer successively and kneaded for suflicient time to completely incorporate one increment before another increment is added.

Grains can be formed by compression molding, or extrusion. With the higher oxidant loadings compression molding is preferred.

The curing temperature will generally be in the range of 70 to 250 F., preferably between 140 and 200 F. The curing time must be long enough to give the desired mechanical properties in the propellant. The time will generally range from around three hours when the higher curing temperatures are employed to about 28 days when curing is effected at lower temperatures.

EXAMPLE I Propellants containing activated charcoal in accordance with the invention were prepared and compared with similar conventional propellants containing no activated charcoal.

A 1,3-butadiene-2-methyl-5-vinylpyridine rubbery copolymer was prepared by emulsion polymerization at 41 F. according to the following polymerization recipe.

Fifty-five runs were made using the above polymerization recipe. The latex was masterbatched with 19.5 parts of Philblack A (a trademark of Phillips Petroleum Company for a low abrasion furnace carbon black) per 100 parts of rubber. The black masterbatch was then acid coagulated, washed with Water, and dried. The average conversion for these 55 runs was in 17.0 hours. The amount of modifier used in each run was in the range of 0.60 to 0.80 part by weight.

3.0 parts by weight of additional low abrasion furnace carbon black were milled into the copolymer prepared as described above to give a Bd/ MVP copolymer masterbatch containing 22.5 parts of carbon black per parts of rubber.

A propellant masterbatch was prepared by adding two parts by Weight (based on the finished propellant) of the above-described Bd/MVP copolymer to a 0.7 gallon Baker-Perkins mixer. Said copolymer was kneaded for four minutes. Two parts by weight of liquid polybutadiene having a Saybolt Furol viscosity at 100 F. of about 1500 and 8.65 parts by weight of ammonium nitrate were then added to the copolymer in said mixer. The compression ram was lowered and the contents of the mixer were kneaded for 10 minutes after which the thus prepared propellant masterbatch was removed from the mixer.

Four propellant compositions were then prepared using the above-described propellant masterbatch. For each of said four propellants, the remainder of the oxidizer component (ammonium nitrate) to be incorporated therein was divided into four equal increments. A portion of the propellant masterbatch suflicient to give the final desired composition when mixed with the remaining ingredients of the composition was placed in the mixer. One increment of said oxidizer was added to the propellant master- 7 batch and the mixture was kneaded for two minutes. A second increment was then added to the mixture in the mixer and kneading was carried out for an additional two After the above compositions had been thoroughly mixed, portions thereof were extruded into strands approximately inch in diameter. Said strands were then minutes. A third increment of said oxidizer was then cured and burning rates were determined. The results added to said mixture and kneading was carried out for of these burning rate tests are given in Table IV below. an additional six minutes. The final increment was added TABLE IV and kneading of the mixture was carried out for an additional eight minutes. The desired quantity of activated Burning Rate Burning Rate, charcoal and/or ammonium dichromate was then added propellant fi j Exponent to said mixture in the mixer and kneading was carried out for an additional ten minutes. In all of said kneading M74 M6 steps, the solids incrementally added were thoroughly in- 0.171 0.56 corporated into the binder before addition of additional solids. While this invention has been described employing a After the addition of the activated charcoal and/or ambinder composition comprising a copolymer of a conmonium dichromate the mixture was removed from the jugated diene with a polymerizable heterocyclic nitrogen mixer and burning rate test strands and tensile specimens base of the pyridine series, such as vinylpyridine and for each propellant mixture were prepared by compression various alkyl-substituted derivatives, it is to be understood molding at 8,000 to 10,000 p.s.i. Said strands and tensile that the corresponding quinoline and isoquinoline cornspecimens were cured 24 hours at 190 F. before being pounds are also applicable, i.e., vinylquinolines, vinylisotested. quinolines and various alkyl-substituted derivatives of Table I below gives the composition of the said four these compounds. propellants and shows the results of burning rate tests on Various other modifications of the invention can be said burning rate test strands. Table II below shows the made or followed by those skilled in the art, in view of results of physical tests carried out on said tensile t above disclosure, Without departing from the Spirit specimens. or scope of the invention. TABLE I Composition Parts Percent Parts Percent Parts Percent Parts Percent by wt by wt. by wt by wt. by wt by wt. by wt by wt.

2 1.92 2 1.92 2 1.92 2 1.92 2 1.92 2 1.92 2 1.92 2 1.92 s. 65 8.32 8.65 8.32 8.65 8.32 8.65 8.32 Ammonium Nitrate 83.35 80.15 83.35 80.16 83.35 80.16 85.35 82.08 Ammonium Dtchromate 4 3. 84 l 0.96 2 1.92 Norlt A (activated charcoal) 4 3184 7 6. 72 8 7. 68 4 3. 84

Totals 104.0 100.00 104.0 100.00 104.0 100.00 104.0 100. 00

Burning Rate:

Inches per second A 1,000 p.s.t 0. 0. 0. 45 0.35 Exponentrn 0. 00 0. 55 0. 60 0. 70

Contained 22.5 parts of carbon black (furnace black) b Ammonium nitrate used in propellants 1, 2, and 4 contained approximately 10 weight percent potassium nitrate.

@ Particle size 3 to 12 microns.

TABLE II Propellant No. Elongation, Tensile, Modulus,

Percent p.s.i. p.s.i.

EXAMPLE II Two propellants having the composition given in Table III below were prepared by first thoroughly mixing the binder ingredients to form a binder mixture and then adding the oxidizer ingredient in four equal subsequent additions.

I A furnace black.

2 5,8,11,13,16-19-hexoxa-n-tr1cosane.

3 A physical mixture containing 65 percent of a complex diarylamine ketfilne reaction product and 35 percent of N,N-diphenyl-p-phenylenediam e.

per parts of copolymer. was phase stabilized with potassium nitrate and We claim:

1. A propellant composition consisting essentially of, in parts by weight of said composition: from 4 to 16 parts of a binder component comprising (1) from 2 to 10 parts of a copolymer prepared by copolymerizing (a) a conjugated diene containing from 4 to 8 carbon atoms per molecule with (b) a substituted heterocyclic nitrogen base selected from a group consisting of pyridine, quinoline, alkyl substituted pyridine, and alkyl substituted quinoline, wherein the total number of carbon atoms in the nuclear alkyl substituents is not more than 15 and wherein R is selected from the group consisting of a hydrogen atom and a methyl radical, and (2) from 2 to '6 parts of a liquid polybutadiene; from 88 to 94 parts of a solid inorganic oxidizing salt as an oxidant component; and from 4 to 12 parts of activated charcoal.

2. The composition of claim 1 wherein said heterocyclic nitrogen base is Z-methyl-S-vinylpyridine and said conjugated diene is 1,3-butadiene.

3. The composition of claim 1 wherein said heterocyclic nitrogen base is 2-vinylpyridine and said conjugated diene is 1,3-butadiene.

4. The composition of claim 1 wherein said hetero- 9 cyclic nitrogen base is 2-ethyl-5-vinylpyridine and said conjugated diene is 1,3-butadiene.

5. A propellant composition consisting essentially of, in parts by Weight of said composition: from 2 to 4- parts of a copolymer prepared by copolymerizing (a) a conjugated diene containing from 4 to 8 carbon atoms per molecule with (b) a substituted heterocyclic nitrogen base selected from a group consisting of pyridine, quinoline, alkyl substituted pyridine, and alkyl substituted quinoline, wherein the total number of carbon atoms in the nuclear alkyl substitaents is not more than 15 and wherein R is selected from the group consisting of a hydrogen atom and a methyl radical, said copolymer having carbon black incorporated therein in an amount of from to 30 parts by Weight per 100 parts by Weight of said copolymer; 2 parts of a liquid polybutadiene; from 92 to 94 parts of ammonium nitrate; from 4 to 8 parts of activated charcoal; and from 0 to 4 parts of a burning rate catalyst other than said activated charcoal.

6. The composition of claim wherein said heterocyclic nitrogen base is Z-methyl-S-vinylpyridine and said conjugated diene is 1,3-butadiene.

7. The composition of claim 5 wherein said heterocyclic nitrogen base is 2-vinylpyridine and said conjugated diene is 1,3-butadiene.

8. The composition of claim 5 wherein said heterocyclic nitrogen base is 2-ethyl-5-vinylpyridine and said conjugated diene is 1,3-butadiene.

9. The composition of claim 5 wherein the amount of said copolymer is 2 parts by weight of said composition.

10. A propellant composition which consists essentially of, in parts by weight of said composition: from 2 to 10 parts of a copolymer of (a) a conjugated diene containing from 4 to 8 carbon atoms per molecule and (b) a RI GH2=O/ substituted heterocyclic nitrogen base selected from the group consisting of pyridine, quinoline, alkyl substituted pyridine, and alkyl substituted quinoline, wherein the total number of carbon atoms in the nuclear alkyl substituents is not more than and wherein R is selected from the group consisting of a hydrogen atom and a methyl radical, said copolymer having carbon black incorporated therein in an amount of from 0 to 30 parts per hundred parts of said copolymer; from 26 parts of a liquid polybutadiene; from 88 to 94 parts of ammonium nitrate; from 4 to 12 parts of activated charcoal; and from O to 4 parts of ammonium dichromate.

11. The composition of claim 10 wherein: said diene is 1,3-butadiene; and said heterocyclic nitrogen base is 2-rnethy1-5-vinylpyridine.

12. The composition of claim 10 wherein: said diene is 1,3-butadiene; and said heterocyclic nitrogen base is 2-vinylpyridine.

13. The composition of claim 10 wherein: said diene is 1,3-butadiene; and said heterocyclic nitrogen base is 2-ethyl-5-vinylpyridine.

14. A propellant composition consisting essentially of in parts by weight of said composition: from 88 to 94 parts of an inorganic oxidizing salt as an oxidizing component; from 4 to 16 parts of a binder component comprising a copolymer of (a) a conjugated diene containing from 4 to 8 carbon atoms per molecule with (b) a substituted heterocyclic nitrogen base selected from the group consisting of pyridine, quinoline, alkyl substituted pyridine, and alkyl substituted quinoline, wherein the total number of carbon atoms in the nuclear alkyl substituents is not more than 15 and wherein R is selected from the group consisting of a hydrogen atom and a methyl radical; and from 4 to 12 parts of activated charcoal as the sole curing agent.

15. A propellant composition consisting essentially of, in parts by weight of said composition: from 4 to 16 parts of a binder component comprising from 2 to 10 parts of a copolymer prepared by copolymerizing (a) a conjugated diene containing from 4 to 8 carbon atoms per molecule with (b) a substituted heterocyclic nitrogen base selected from a group consisting of pyridine, quinoline, alkyl substituted pyridine, and alkyl substituted quinoline, wherein the total number of carbon atoms in the nuclear alkyl substituents is not more than 15 and wherein R is selected from the group consisting of a hydrogen atom and a methyl radical; from 88 to 94 parts of a solid inorganic oxidizing salt as an oxidant component; and from 4 to 12 parts of activated charcoal.

References Cited in the file of this patent UNITED STATES PATENTS 1,766,269 Thiecke June 24, 1930 1,826,846 Tschunkur Oct. 13, 1931 2,313,693 Winkelmann Mar. 9, 1943 2,334,526 Allison Nov. 16, 1943 2,356,965 Allison Aug. 29, 1944 2,363,569 Caldwell et al. Nov. 28, 1944 2,646,596 Thomas et al. July 28, 1953 2,857,258 Thomas Oct. 21, 1958 2,877,504 Fox Mar. 17, 1959 FOREIGN PATENTS 655,5 Great Britain July 25, 1951 

1. A PROPELLANT COMPOSITION CONSISTING ESSENTIALLY OF, IN PARTS BY WEIGHT OF SAID COMPOSITION: FROM 4 TO 16 PARTS OF A BINDER COMPONENT COMPRISING (1) FROM 2 TO 10 PARTS OF A COPOLYMER PREPARED BY COPOLYMERIZING (A) A CONJUGATED DIENE CONTAINING FROM 4 TO 8 CARBON ATOMS PER MOLECULE WITH (B) A 